021 |
INTERPRETATION OF PHOTOFLUOROGRAMS OF ACTIVE PULMONARY
TB PATIENTS FOUND IN EPIDEMIOLOGICAL SURVEY AND THEIR FIVE YEAR FATE |
GD Gothi, AK Chakraborty & GC Banerjee: Indian
J TB 1974, 21, 90-97. |
In this study the material from Five year
study of Epidemiology of Tuberculosis (1961-68) has been analysed
to find out an improved method of interpretation of chest X-rays
to get accurate estimation of prevalence of suspects
in the community. The population of a random sample of 119 villages
from the three taluks of Bangalore district was surveyed four times
with intervals of 1½ to 2 years by tuberculin testing, 70mm
chest photofluorography and sputum bacteriology. Out of 45,434 persons
X-rayed during the first survey, 590 were read as active pulmonary
tuberculosis on the basis of single picture interpretation by two
independent readers. Of them, 460 being sputum culture negative
were classified as initial suspects and these were reviewed
in this study by the panel of three readers together by the method
of joint reading. The interpretation was done comparing
the serial X-rays of individuals taken at intervals along with other
available examination results and personal data. Out of 460 initial
suspects only 110 (23.9%) were confirmed as suspects,
the remaining were judged as non-tuberculous and/or inactive tuberculous
(62.2%) and normals (13.9%).
Fates on five year follow up were compared between
85 confirmed suspects and 385 initial suspects.
The mortality and sputum positive status were found more among the
former group i.e., 23.5 and 25.5 and 14% and 7.2% respectively.
Radiologically, 48.7% of the confirmed suspects and only 10% of
the initial suspects could be classified as suspects at 5th year
follow up. Incidence of bacillary disease among the confirmed suspects
was also found higher. On the basis of joint reading
and five year follow up study, the limitations of single picture
interpretation resulting in considerable over diagnosis were clearly
seen. The comparative reading of serial X-rays along with other
examination results did help in the better assessment of etiology
and activity status of disease. Of the X-rays read as non-tuberculous
and inactive tuberculous when reviewed by joint reading
method, about 67 more suspects could be added. Even then the estimates
of prevalence of suspects based on single film interpretation
which are widely used in India appear to be about 3 times the actual
prevalence.
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KEY WORDS: FATE, SUSPECT CASE, X-RAY, JOINT
READING, SINGLE PICTURE, OVER DIAGNOSIS. |